Telephone-exchange system



Patented June 2, 1925,

Aienne@ :UNITED STATES !?ATEN'.l` QFFICE.

CHARLES L. GOODRUI, OF NEW YORK, N. Y., ASSIG'N'ORl TO TNESTERN ELECTRIC COM- PANY, 1NCOR]?O'.R\.TED. Ol? NEVI YQEK, N. Y., CORPBATIQN 0F NEVI TELEPHONE-EXCHANGE Application filed Qctobei: 25,)1920, Serial No. 419,214.

description.

l This invention relates to telephone ci:-

:hanp'e systems and more partimilarly to circuit arrangements for private branch exchanges, where such exchanges are to be used in connection with a vmain central 5 office. Y f

The object of the invention is to provide an improved circuit arrangement whereby a subscriber of the private branch exchange may at all times, selectively extend his line to an operators position ot' the private branch exchange, or over an idle one of a plurality ot trunks leading` to the main central oflice. In accordancewith the present invention,

D the subscribers line is provided with a nonninnerical switch in addition to the usual line jack and line signal at the private branch exchange. In addition to the usual equipment for la common battery substation, the subscribers set is provided With a resist ance in the line circuit, the resistance being normally sh0rt-circuited byineans'ot a key. If the main central office is ot theautomatic type, the substation will also. be equipped With the usual impulse sender for the purpose of setting the switches at the main central ofiice. Removal of the receiver from the switchhook causes the non-numerical switch to be actuatedv to extend the line over an idle one of a plurality of trunks leading to the central o'lice, whereas actuation of the key and removal et the receiver from the switchhook causes the line signal at the operators position to be actuated.

More specifically, each line is provided with a pair of line relays, one of' which is marginal.` Actuation of both of the line relays causes the operation of a magnet Ycontrolling the actuation of the non-numerical switch, and actuation of one 'of the line relays causes the actuation ot the line signal at the operator-s position.

Referring;n to the drawing which shows only so much. of a telephone exchange system as is necessary for a complete understanding' ot the invention, there is shown at A, a subscribers station, connected to a. jack l() teri'ninatingat the operators position, and having' access to a non-numerical switch F, located at the private branch exchange. Associated with a plurality of line switches there may be a master switch schematically shown at M. rlhe 'function of the master switch is to keep the contacts of the switch F in operative relationship U5 with an idle trunk. The line anclnxaster switches may be ot the general type described in U. S. Patent No. 1,203,166 to B. D. Willis of October 3l. 1916. At O there is shown a portion oi a line circuit, which may also terminate at the private branch exchange. At B there is shown a cord circuit for interconnectinn` lines of the private branch exchange. C represents schematically a portion of a connector circuit 'f5 at the main central oiiice connected by a trunk circuit havingl conductors 2l and 22 extending' to the private branch exchange. D represent-s a portion of the line ot a subscrbers station terminating in an auto- SU matic switch in the main central otlice.

The invention will be more readily understood from a detailed description of the operation of the system.

The party at station A desiring to extend 35 his line over one of a plurality ofk trunks leading to the main central oliice, removes the receiver from the svvitchhoolr, Which causes the operation ot relays 5 and 6 over a path extending from battery, through the winding of relay 6, back contact and inner left-hand armature of relay 7, through the substation loop, outer left-hand armature and back contact of relay 7, and Winding of relay 5 to ground. Relays 5 and 6 in oper- 95 ating, complete a circuit through the low resistance.y right-hand Winding of relay 7, thereby causing the attraction of the armature 70. Attraction of the armature 70 causes ythe closure o the contacts 27, 28 and 100 during each interruption.

29 olf the switch ll` in the well known manner thereby extending the line of the calling station through to the line relay 2O ot' the connector` switch. For the purpose olf simplicity,v the line switch at the private branch exchange is shown connected directly to the connector "C at the autoi'natic exchange over a trunk line having the conductors 2l and It will be understooch however, that the conductors 2l and 22 extending from the private branch exchange to the main central cnice may terminate in a non-numerical switch, or a selective switch of the automatic exchange. As soon as theswitcn at the -pri- `fatebranch eachange is operated to extend 'zthe line of station A. to the connector switch,

relay Q0 ot' the connector and relay 8 offthe lineswitch are energizedoyer a patlrextending from ground, right-hand winding ot .relay 20,lconductor 22, contacts 28 oi' the line switch F, through to the windingot relay 8, through the substation loop, contacts 27 of the line switch conductor 2l., and -lettihand winding ot relay Q0 to grounded battery. lRelay 8 thereupon attracts its .arzmatui-e and completes a .circi'lit for slowtorelease relay 30 Relay v8 in operating also connects ground to :the sleeve ot 4jack l() to render said ,jack busy. Relay 30 in operating, completes a circuit 1at its right-hand' armature and trent contact through the high resistance. winding ol relay 7. The left-hand :armatures of relay 7 are then attracted7 thereby disconnecting .the rline .relays 5 and -6 from the-calling line. Relays 5 and -6 are preferably of the .slow-to-release type in order to insure the attraction .ort the armature or vplunger 70 ot the relay 'l'. Relay 30 in attracting its left-hand armature connects grountlny through contacts 29 oit the line switch ll to contact. 23 oit' the vmaster switcln schematically indicated at M.. The starting magnet Q4 o t the master switch is then operated and causes the masltery switch to advance the remaining plungers into operative .relationship with the next idle trunk Vin the well known manner.

The subscriber at station A.. niay now operate the sender t3 ltor the purpose .ot setting the connector switch upon the terminals oit the desired line in the manner well known in the art. Relay 8 responds to each interruption in the line circuit5 thereby momentarily opening the circuit tor relay 30 Relay 3() how eyer7 being' of the slow-to-release typeyl-does not retract its armatures during the sending of a series of impulses. After the require-d number of impulses have been sent to set the brushes l0 and 41 upon the terminals l2 and ill-lof the desired line, ringingcurrent is automatically projected over vthe line leading to the desired substation D in the inan-` ner well-known in the art'. When the subscriber at station D responds, ringingy current is automatically disconnected and the subscribers A and D are connected for con- Vcrsation. The subscriber at substation A. is supplied with talking current through the winding'ot relay 2O of the connector (l and the subscribers station D islsupplied with talking current through tthe windings ol3 relay 50 ot the connector C. Upon tht` completion of conversation and restoration oi" the receivers of the calling and called subscribers to their respective switcheoks. all apiiiaratus `is restored to normal in the manner well known in the art.

It will next be assumed that the subscriber at station A desires connection with another station of the private ibi-anch exchange. The subscriber at station A thereupon actuates the ynon-locking key l and yremoves the receiver 2 from the 'switchhook 3, thereby connecting the resistance e fin the line circuit.

and back contact of relay 7, and winding oit relay 5 to ground. Relay 6 in operating completes Aa circuit for lrelay 7l over a path extending from ground, armature 'and iront contact of relay G,D armature and yback contact of relay v5, and 'winding of relay 7l to .grounded battery. Relay 71 in operating completes a circuit 'at its inner lethaiiid armature and front contact for the lighting of line signal 1.2, and `at its right-'hand armature, locks up under control loff 'slow-.tomelease .relay 30. Relay 7l .is preferably-of the slow-to-release type in order to insure its being locked up before alfine .relay 6 retracts its armature. At the outer lett-hand armature and front Contact of relay 71., a circuit is completed through the high resistance Winding of relay 7, thereby causing said .relay to attract its left-hand armatures, whereupon the line relays 5 and 6 are disconnected from the calling line. Relay 6 is also preterably slow-to-release vin order `to insure the .locking up of relay 7l before said relay 6 retracts its armature. Trhe roperator at the private branch noting the lighting Aor' line signal l2, inserts the answering plug ll of the cord circuit B into the jack 10, whereupon supervisory .relay 60 of Ithe cord circuit B is energized over a path extending from ground, lower left-hand winding ot repeating coil 611, winding oft relay 60. rings ott ,plug vl1 and jack l0, through the substation loop,-tips of jack l0 and plug 11 and upper left-hand winding of repeating coil 6l to battery. ySupervisory lamp 62 is thereby prevented from lighting. The operator then lll icc

actuates a listening key (not shown) tor the purpose of ascertaining the wants oit the calling subscriber. Assuming that the sul)n scriber of station O is desired, the operator will insert the plug 14: of the cord circuit B into the jack l5 of the desired line and then actuate a ringing key (not shown) for the purpose of signaling the subscriber of station O.

Upon the response of the called subscriber, supervisory relay 16 of the cord cin cuit B will be actuated, thereby shunting the supervisory lamp 17 of the cord circuit B in the well-known manner. Upon completion of conversation and restoration ot the receivers to the switchhooks at the calling and called substations, supervisory lamps 62 and 17 will be lighted, indicating to the operator that conversation has been completed. The operator noting these signals, removes the plugs 11 and 14y from their respective jacks, thereby restoring all apparatus tonormal. The system is then ready for the next call.

It will be understood that the line circuit herein disclosed is equally well adaptable tor use in connection with a manual main central office instead of' an automatic main central office as shown. In such case, a line relay at the manual central o'tlice would be energized to display a signal before an operator, when the non-numerical switch F is actuated instead of the relay 2O of the connector switch C.

What is claimed is :A

l. In a telephone exchange system, a subscribers station, a key and a resistance thereat, a pair of line conductors extending from said station to an exchange, a line jack and a line signal for said station at said exchange, a line switch orsaid station at said exchange, and means at said exchange controlled by said key and resistance over the pair of line conductors in series for selectively operating said line signal or said line switch.

2. In a telephone exchange system, an exchange, a subscribers line terminating therein, a plurality of line relays ttor said line, manual and automatic connective link circuits at said exchange for extending a call from said line, means including a resistance normally shunted by subscriber controlled means for selectively controlling the operation of said line relays over said line conductors in series to selectively extend the calling line to said manual or automatic connective terminals.v

3. In a telephone exchange system, a subscribers station, a line circuit consisting of two conductors extending from said subscribers station to a private branch exchange, a main central oilice, a plurality of trunk circuits extending from said exchange to said central office, a line switch at said exchange adapted upon actuation to extend said line circuit over an idle one of said trunk circuits to said central office, a line signal for said line at said exchange, a key and a resistance connected in said line circuit at the subscribers station, said resistance being normally shunted by said key, and means dependent upon the actuation or non-actuation of said key when a calling party initiates a call for selectively operating the line vsignal or the line switch.

4. In a telephone exchange systeni, a twoconductor `line circuit, a subscribers station connected thereto having a switch hook and a nou-locking key, aline signal, a line switch 'for said station having access to a plurality of trunks, and means controlled over the two conductors of said line circuit in series whereby upon the actuation ot said key and switchhook said line signal is operated and upon the actuation ot' said switchliook alone said line switch is operated to extend the calling line to an idle trunk and to prevent the operation ot said -line signal. l

5. In a telephone exchange system, a tele phone line terminating in a jack at a .first exchange, astation thereon, a line signal associated with said jack for said station, an automatic switch accessible to said station, a pair of line relays for said line, a second exchange, a trunk line extending from said first to said second exchange, a magnet for Vsaid switchadapted upon actuation to connect said telephone line to said trunk line, a circuit completed for said magnet when the pair of line relays are actuated, a circuit completed for said line signal when only one of said line relays is actuated, and manual switches at said exchange for causing said line circuit to selectively actuate one or both of said line relays.

6. In a telephone exchange system, a first exchange, subscribers lines terminating therein, a second exchange, trunk lines extending between said exchanges, automatic switches at said first exchange, a line signal for each otsaid lines at said first exchange, and means under the control of a calling subscriber at said first exchange and operable over the two conduct-ors of said line in series for selectively operating one of said automatic switches to extend said line to said second exchange or to operate the line signal of the calling line.

7. In a telephone exchange system, a first exchange, a subscribers line terminating therein in a jack, a second exchange, a plurality of trunk lines extending from said first exchange to said second exchange, a line signal for said line associated with said jack, a line switch for said line adapted upon actuation to connect said calling line to an idle one of said trunk lines, a pair of line relays for said calling line, means opierahle when Vhoth of said line, relays Yareactirated to actuate said line switch, means operable when one 4of said `line Arelays'is actuated to actuate said line signal, and a switching `device at the .calling substation for irdetern-lining the operation ci? said relays.

8. 'In a telephone system, 'a first exchange, a plurality of subscribers lines terminating ther'eat, a plurality ot' non-numerical switches at said 4first eXcha-nge,a second texchange, a `plurality ot' trunk lines `extending from said liirst tosaid second exchange, a. manually operable connecting circuit at said first exchange for `inteconneet-ing 'subscribers lines, a `key at each station oit' a 'line terminating at the first exchange, imeains operable in response to the removal of the receiver and actuation of the lrey at a station of a calling line for initiating la call'at the first exchange, and means operable over the two conductors of said line in series in 'response to the removal of Vthe receiver only for actuating Vone of said non-numerical switches to initiate a call over a trunk line extending to the second exchange.

9. In a telephone system, a central ojtiice, a suhscribers line terminating thereat, subscriber controlledv means including a nonlocking' normally closed key', sliun'ted by a "resistance, in serial relation with 'said line, manual and automatic connecting link cir,- cuits at said central otiice for extending said line, and means at the central oli'ice 'controlled hy said key for selectively extending the calling line to said manual orsaid automatic link circuit.

i0. iIn a telephone system, an exchange a subscribers line 'terminatingthereat, auto- 'matic and manual connecting link circuits at said ezichange tor vextending a call from "said line, a station 'for said line having a resistance, a key and a switch hook thereat, said resistance being normally short-circuited hysaid key, and a pairoi relays at the central oiiice, one of said relays operating 'when said switclrhook lis operated to extend the line to one oi' said connecting link circuits and both of said relays operating when said key and said sWitchhool are operated to extend the line to the 'other of said connecting' circuits one of isaid relays being marginal and inoperative When 'said resistance is included in the line circuit.

Il. In a telephone exchange system, a

calling` subscrihers station, va 'pa-ir ot line CHARLES L. GODRIIM.

and oper'fa DISCLAIMER.

1,540,066-(771m1les L. Goodman, New York, N. Y. TELEPHONE-EXCHANGE SYSTEM. Patent dated June 2, 1925. Disclaimer led May 24, 1928, by the assignee, 'll/*estera E Zectrc Company, [incorporated l'lereby enters this disclaimer to the said claims of said Letters Patent which are in the-following Words to wit:

2. In a telephone exchange system, an exchange, a subscribers line terminating therein, a plurality of, line relays for said line, manual and automatic connective link circuits a said exchange 'f for extending a call from said line, means including a resistance mallyshunted by subscriber controlled means for selectively controlling th peration 1,0, aid line relays over said line.- conductors in series to selectively 'extendf th "call J1-line to saidf-manual or automatic connective terminals.

' hnge system, a first exchange, subscribers lines terminating angff'trunk lines` extending between said exchanges, automa-tic d first exchange, a line signal for each of said lines .at said rst eansunder the control of a calling subscriber at sa' rst exchange er the two conductors of said line in series for sel Wely operating one of sai automatic switches to extend said line to said secon ex ange or to operate the line signal of the calling line,

9; In a telephone system, a central oiiice,j;subscribers line terminating thereat, subscriber controlled means incliiding a nnlolcking normally closedkey, shunted by a resistance, in serial relation iv'th said line, manual and automatic connecting link circuits at said central otice for xtending said line, and means at the central oi'tice controlled by saidkey for selectively extending the calling line to said manual or said automatic link circuit.

10. In a telephone system, an exchange, a subscriber-s line terminating thereat, automatic and manual connecting link circuits at said exchange for extending a call -from said line,",a station Jfor said line having a resistance, a key and a switchhook thcreat, said resistance being normally sh0rt-circuited by said key and a pair of relays at the central office, one of said relays operating when said switchhook is operated to extend the line to one of said connecting link circuits and both ot' said relays operating when said key and said switchhook are operated to extend the line to the other of said connect-ing circuits, one of said relays being marginal and inoperative when said resistance is included in the line. circuit.

11. In a telephone exchange system, a calling subscribers station, a pair ot line conductors extending from saidvstation to an llexchange, a manual connecting link circuit at said exchange, an automatic; switch, and means controlled from said station over the pair of line conductors in series for selectively extending the calling station to said manual link circuit or to said automatic switch.

[Oycz'al Gazette June 5, 1928.]

therein, a secon switches at 

